Ultra-fine particle catalysts for carbonaceous fuel elements

ABSTRACT

The present invention provides fuel elements comprising a carbonaceous material and a catalyst composition comprising ultrafine particles of a metal oxide and/or metal. The present invention additionally provides smoking articles demonstrating reduced amounts of carbon monoxide in the smoke-like aerosol produced by the smoking article. In a further aspect, the present invention provides methods and apparatus for the simultaneous resolution and quantification of a carbon monoxide content and a carbon dioxide content of a gaseous mixture.

Field of the Invention

The present invention relates generally to fuel elements for smokingarticles, and more particularly to fuel elements comprising acarbonaceous material and ultrafine particles. In an embodiment, thefuel elements may be utilized in smoking articles to reduce the amountof carbon monoxide in the mainstream smoke and improve the thermalefficiency of the fuel.

BACKGROUND OF THE INVENTION

Cigarettes are popular smoking articles that use tobacco in variousforms. Descriptions of cigarettes and the various components thereof areset forth in Tobacco Production, Chemistry and Technology, Davis et al.(Eds.) (1999).

Cigarettes generally include a substantially cylindrical rod-shapedstructure and include a charge, roll or column of smokeable materialsuch as shredded tobacco (e.g., in cut filler form) surrounded by apaper wrapper thereby forming a so-called “tobacco rod.” Normally, acigarette has a cylindrical filter element aligned in an end-to-endrelationship with the tobacco rod. Typically, a filter element includescellulose acetate tow circumscribed by plug wrap, and is attached to thetobacco rod using a circumscribing tipping material. It also has becomedesirable to perforate the tipping material and plug wrap, in order toprovide dilution of drawn mainstream smoke with ambient air.

Carbonaceous materials can be employed as components of combustiblematerial components in a smoking article that are designed to burn andprovide heat to aerosolize physically separate aerosol-formingmaterials. Cigarettes having carbonaceous combustible materialcomponents have been marketed by the R. J. Reynolds Tobacco Companyunder the tradenames Premier and Eclipse. See, for example, U.S. Pat.No. 4,708,151 to Shelar et al.; U.S. Pat. No. 5,016,654 to Bernasek etal.; U.S. Pat. No. 4,991,596 to Lawrence et al.; U.S. Pat. No. 5,038,802to White et al.; U.S. Pat. No. 4,793,365 to Sensabaugh et al.; U.S. Pat.No. 4,961,438 to Korte; U.S. Pat. No. 4,991,606 to Serrano et al.; U.S.Pat. No. 5,020,548 to Farrier et al.; U.S. Pat. No. 5,076,297 to Farrieret al.; U.S. Pat. No. 5,148,821 to Best et al.; U.S. Pat. No. 5,178,167to Riggs et al.; U.S. Pat. No. 5,183,062 to Clearman et al.; U.S. Pat.No. 5,345,955 to Clearman et al.; U.S. Pat. No. 5,551,451 to Riggs etal.; and U.S. Pat. No. 5,595,577 to Bensalem et al. The disclosure ofeach of these patents is incorporated herein by reference. See, also,Chemical and Biological Studies on New Cigarette Prototypes that HeatInstead of Burn Tobacco, R. J. Reynolds Tobacco Company Monograph(1988).

It also has been suggested to incorporate non-combustible materials intothe carbonaceous combustible material components of certain types ofsmoking articles. See, for example, U.S. Pat. No. 5,040,551 to Schlatteret al.; U.S. Pat. No. 5,211,684 to Shannon et al.; U.S. Pat. No.5,240,014 to Deevi et al.; and U.S. Pat. No. 5,258,340 to Augustine etal. The disclosure of each of these patents is incorporated herein byreference.

It would be desirable to provide a fuel element for a smoking articlethat reduces the amount of carbon monoxide present in the aerosol of thesmoking article. It would additionally be desirable to provide a fuelelement that displays a more efficient combustion.

SUMMARY OF THE INVENTION

The present invention provides fuel elements comprising ultrafineparticles. In an embodiment of the present invention, the ultrafineparticles catalyze the conversion of carbon monoxide to carbon dioxide,thereby reducing the amount of carbon monoxide present in the combustiongases produced by burning of the fuel element. In a smoking articleembodiment, a fuel element comprising ultrafine particles reduces theamount of carbon monoxide present in the aerosol and demonstrates a moreefficient combustion by producing more energy per gram of fuelcombusted.

The present invention also provides methods for altering the performancecharacteristics of smoking articles to reduce the amount of carbonmonoxide present in aerosol produced by the smoking article.

In one aspect, the present invention provides a fuel element comprisinga carbonaceous material and at least one catalyst composition, thecatalyst composition comprising ultrafine particles.

In another aspect, the present invention provides a method for reducingthe amount of carbon monoxide produced by an article comprising a fuelelement, the method comprising incorporating ultrafine particles in thefuel element.

In a further aspect, the present invention provides a smoking articlehaving reduced amounts of carbon monoxide in the aerosol produced by thesmoking article. In an embodiment, the smoking article comprises: a fuelelement comprising a carbonaceous material and ultrafine particles.

In a still further aspect, the present invention provides methods andapparatus for the simultaneous relative quantification of carbonmonoxide and carbon dioxide in a gaseous mixture. In an embodiment, themethod comprises injecting a gaseous mixture into a split singleinjector of a gas chromatograph for splitting the gaseous mixture ontotwo chromatographic columns; resolving the carbon monoxide content ofthe gaseous mixture on a first chromatographic column; simultaneouslyresolving the carbon dioxide content of the gaseous mixture on a secondchromatographic column; and detecting and quantifying the resolvedcarbon monoxide and carbon dioxide contents with a mass spectrometer.Embodiments of the method may be utilized to simultaneously quantify therelative amounts of carbon monoxide and carbon dioxide in aerosol from asmoking article.

An advantage of the present invention is that that fuel elements of thepresent invention may be used in applications where it is desirable toreduce amounts of carbon monoxide.

Further features and advantages of the present invention are set forthin the following more detailed description.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 illustrates a smoking article according to an embodiment of thepresent invention.

FIG. 2 illustrates a method according to an embodiment of the presentinvention.

FIG. 3 illustrates an apparatus according to an embodiment of thepresent invention.

FIG. 4 illustrates an ion chromatogram of a standard gaseous mixtureresolved on dual columns according to an embodiment of the presentinvention.

FIG. 5 illustrates an ion chromatogram of a standard gaseous mixtureresolved on a Molsieve column according to an embodiment of the presentinvention.

FIG. 6 illustrates an ion chromatogram of a standard gaseous mixtureresolved on a Carbon Plot column according to an embodiment of thepresent invention.

FIG. 7 illustrates an ion chromatogram of heated tobaccos resolved ondual columns according to an embodiment of the present invention.

FIG. 8 illustrates an ion chromatogram of cigarette smoke resolved ondual columns according to an embodiment of the present invention.

FIG. 9 illustrates the reduced production of carbon monoxide by carbonupon combustion in the presence of various ultrafine particles accordingto embodiments of the present invention.

FIG. 10 illustrates the reduced production of carbon monoxide bycombustion of carbon and mixtures comprising carbon, Guar gum, graphite,and tobacco in the presence of iron oxide ultrafine particles of varioussizes according to embodiments of the present invention.

FIG. 11 illustrates the reduced production of carbon monoxide bycombustion of carbon in the presence of various metal oxide ultrafineparticles according to embodiments of the present invention.

FIG. 12 illustrates the effect of catalyst compositions on a CO/CO₂ratio when tobacco is pyrolized in the presence of various ultrafineparticles according to embodiments of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

The present invention provides fuel elements comprising a carbonaceousmaterial and at least one catalyst composition. The present inventionadditionally provides articles of manufacture including, but not limitedto, smoking articles. The present invention further provides methods foraltering the performance characteristics of smoking articles. Moreover,the present invention provides methods and apparatus for thesimultaneous quantification of the carbon monoxide content and carbondioxide content of a gaseous mixture comprising these and various otherchemical species.

Reference is made below to specific embodiments of the presentinvention. Each embodiment is provided by way of explanation of theinvention, not as a limitation of the invention. In fact, it will beapparent to those skilled in the art that various modifications andvariations can be made in the present invention without departing fromthe scope or spirit of the invention. For instance, features illustratedor described as part of one embodiment may be incorporated into anotherembodiment to yield a further embodiment. Thus, it is intended that thepresent invention cover such modifications and variations as come withinthe scope of the appended claims and their equivalents.

For the purposes of this specification, unless otherwise indicated, allnumbers expressing quantities of ingredients, reaction conditions, andso forth used in the specification are to be understood as beingmodified in all instances by the term “about.” Accordingly, unlessindicated to the contrary, the numerical parameters set forth in thefollowing specification are approximations that can vary, depending uponthe desired properties sought to be obtained by the present invention.At the very least, and not as an attempt to limit the application of thedoctrine of equivalents to the scope of the claims, each numericalparameter should at least be construed in light of the number ofreported significant digits and by applying ordinary roundingtechniques.

Notwithstanding that the numerical ranges and parameters setting forththe broad scope of the invention are approximations, the numericalvalues set forth in the specific examples are reported as precisely aspossible. Any numerical value, however, inherently contains certainerrors necessarily resulting from the standard deviation found in theirrespective testing measurements. Moreover, all ranges disclosed hereinare to be understood to encompass any and all subranges subsumedtherein, and every number between the end points. For example, a statedrange of “1 to 10” should be considered to include any and all subrangesbetween (and inclusive of) the minimum value of 1 and the maximum valueof 10; that is, all subranges beginning with a minimum value of 1 ormore, e.g., 1 to 6.1, and ending with a maximum value of 10 or less,e.g., 5.5 to 10, as well as all ranges beginning and ending within theend points, e.g., 2 to 9, 3 to 8, 3.2 to 9.3, 4 to 7, and finally toeach number 1, 2, 3, 4, 5, 6, 7, 8, 9 and 10 contained within the range.Additionally, any reference referred to as being “incorporated herein”is to be understood as being incorporated in its entirety.

It is further noted that, as used in this specification, the singularforms “a,” “an,” and “the” include plural referents unless expressly andunequivocally limited to one referent.

In one embodiment of the present invention, a fuel element comprises acarbonaceous material and at least one catalyst composition. Thecatalyst composition comprises ultrafine particles of a metal oxide,metal, or mixtures thereof. As used herein, the term ultrafine particleis generally used to indicate particles with dimensions less than 100nanometers (one nanometer is one-billionth of a meter). The metal oxideand metal ultrafine particles can demonstrate activity for catalyzingchemical reactions, such as the oxidation of carbon monoxide to carbondioxide.

Ultrafine particles suitable for use in catalytic compositions of thepresent invention comprise, but are not limited to, iron oxides (e.g.FeO, Fe₂O₃ and Fe₃O₄), gold, copper, silver, platinum, palladium,rhodium, nickel, zinc, zirconium, other transition metals, metal oxides,and mixtures thereof.

The catalyst compositions comprising ultrafine particles facilitate amore complete production of carbon dioxide by catalyzing the oxidationreaction of carbon to carbon dioxide. In an embodiment whereincombustion of a fuel element generates a gaseous stream comprisingcarbon monoxide, the catalyst composition acts upon carbon monoxide inthe gaseous stream. Ultrafine particles of the catalyst compositions mayalso improve the performance characteristics of a fuel element forparticular applications. For example, the ultrafine particles of thecatalyst compositions can increase the caloric output of a particularfuel.

In an embodiment of the present invention, ultrafine particles of thecatalyst compositions may have an average particle size of 10nanometers, generally between 1 nanometer and 1 micron. In an embodimentof a smoking article of the present invention, the ultrafine particlesmay have an individual particle size of up to about five nanometers. Inanother embodiment of a smoking article of the present invention, theultrafine particles may have an individual particle size between abouttwo and four nanometers.

Ultrafine particles according to the present invention may be producedby a variety of methods including sol-gel synthesis, chemicaldeposition, deposition precipitation, inert gas condensation, mechanicalalloying or high-energy ball milling, plasma synthesis, andelectrodeposition. Using such methods, ultrafine particles can beproduced in various symmetric shapes, such as spheres, cylinders,prisms, cubes, tetrapods and amorphous clusters. In embodiments of thepresent invention, the physical properties of the ultrafine particles,including for example, their electrical, optical, chemical, mechanical,and magnetic properties, may be selectively controlled for example byengineering the size, morphology, and/or composition of the ultrafineparticles. The resulting materials may have enhanced or entirelydifferent properties from their parent materials.

Representative types of ultrafine particles and materials for use in thepresent invention are of the type, and may be produced by methods,described in U.S. Pat. No. 6,503,475 to McCormick U.S. Pat. No.6,472,459 to Morales et al., U.S. Pat. No. 6,467,897 to Wu et al., U.S.Pat. No. 6,479,146 to Caruso et al., and U.S. Pat. No. 6,479,156 toSchmidt et al. and U.S. Published Pat. Applications 2002/0194958 to Leeet al., 2002/014453 to Lilly Jr., et al., 2003/0000538 to Bereman etal., 2002/0167118, 2002/0172826 and 2002/0127351, the disclosure of eachpatent and published application being incorporated herein by reference.

Ultrafine particles for use in the catalyst composition can be obtainedcommercially. For example, Superfine Iron oxide (Fe₂O₃) can be obtainedfrom MACH-1 Inc. of King of Prussia, Pa. Nanopowder Enterprise Inc. ofPiscataway, N.J. is an additional commercial source of ultrafineparticles for use in catalyst compositions of the present invention.

In embodiments of the present invention, the fuel element additionallycomprises a carbonaceous material. The fuel element may additionallycomprise binders like Guar gum, other metallic particles such asaluminum or the like, inert filler material like graphite, and/or burnmodifiers such as sodium or potassium carbonate. In some embodiments,the carbonaceous materials for use in the fuel element include at least50%, by weight carbon. In other embodiments the carbonaceous materialsfor use in the fuel element can include about 60-95% by weight carbon.In still further embodiments, the carbonaceous materials for use in thefuel element can include about 70-80% by weight carbon. The carbonaceousmaterials may be in powder form and may be partially activated. Thecarbonaceous materials may also be heat treated. The carbonaceousmaterials may comprise organic carbon containing materials, for exampletobacco.

The carbonaceous materials of the present invention may be prepared fromseveral starting materials. Suitable starting materials include, but arenot limited to, cellulosic materials with a high (i.e., greater thanabout 80%) alpha-cellulose content, such as cotton, rayon, paper, andthe like. The carbonaceous materials of fuel elements of the presentinvention may be generally prepared by pyrolysis of the startingmaterial at a temperature between about 400° C. and 1300° C., preferablybetween about 500° C. and 950° C., in a non-oxidizing atmosphere, for aperiod of time sufficient to ensure that a large portion orsubstantially all of the starting material has reached the desiredcarbonization temperature. Although the pyrolysis may be conducted at aconstant temperature, it has been found that a slow pyrolysis, employinga gradually increasing heating rate, e.g., from about 1° C. to 20° C.per hour, preferably from about 5° C. to 25° C. per hour, over manyhours, produces a uniform and higher carbon yield.

After cooling, the carbonaceous material may be pulverized. In someembodiments, the carbonaceous material is pulverized to a fine powder.This powder may be subjected to a second pyrolysis or polishing step,wherein the carbonized particulate material, is again pyrolyzed in anon-oxidizing atmosphere, at a temperature between about 650° C. toabout 1250° C., preferably from about 700° C. to 900° C. At this point,the carbonaceous material is ready for combination with the ultrafineparticle catalyst composition along with the other components of thefuel to produce a fuel element composition.

In embodiments of the present invention, the ultrafine particles of thecatalyst compositions can be combined with a carbonaceous material in anumber of ways to produce the fuel element composition. One method ofcombination comprises intimately mixing the carbonaceous material withthe ultrafine particles. Ultrafine particles in dry powder form (e.g.nanopowder) may be mixed directly in a carbon mix along with other dryingredients for extrusion. Alternatively, the ultrafine particles may besuspended in a liquid and the suspension mixed with extrudate.

Another method of combining the ultrafine catalyst compositions with acarbonaceous material comprises forming the carbonaceous material so asto concentrate the catalytic compositions in one or more longitudinalpassageways extending partially through the fuel element. For example,the fuel element may comprise an inner core/outer shell arrangementwhere the outer shell comprises a carbonaceous material surrounding theinner core, and the inner core comprises ultrafine particle catalystcompositions. In some embodiments, the fuel element may include at leastone longitudinal passageway extending at least partially therethrough.

Other methods of combining ultrafine particle catalyst compositions witha carbonaceous material can include wash coating, dipping, painting,spraying, or other methods known to those ordinary skill in the art. Inanother embodiment, the ultrafine particle catalyst compositions can beplaced on inert support located directly behind the fuel element in anend to end relationship. The support for the ultrafine particles can bean inert carbon material such as graphite or a porous material such asalumina or porous graphite.

Once combined with the carbonaceous material, the catalyst compositionmay comprise up to 10% by weight of the resulting mixture. In someembodiments, the catalyst compositions may comprise 1% by weight of theresulting mixture. In another embodiment, catalyst composition maycomprise 0.5% to 2% by weight of the resulting mixture.

The density of a fuel element according to some embodiments of thepresent invention can be generally greater than about 0.5 g/cc, greaterthan about 0.7 g/cc and greater than about 1 g/cc.

The overall length of the fuel element, prior to burning, can begenerally less than about 20 mm, often less than about 15 mm, and can betypically about 12 mm. However, shorter fuel elements may be used ifdesired, depending upon the configuration of the cigarette in which theyare employed. In an embodiment, the overall outside diameter of the fuelelement can be less than about 8 mm, less than about 6 mm, and can beabout 4.2 mm.

The carbonaceous and binder portions of the fuel compositions usefulherein may be any of those carbonaceous and binder materials describedin the patents recited in the Background of the Invention, supra.Several carbonaceous and binder materials are described in U.S.application Ser. No. 07/722,993, filed 28 Jun. 1991, now U.S. Pat. No.5,178,167 the disclosure of which is hereby incorporated herein byreference.

In a further aspect, the present invention provides smoking articles. Inan embodiment, a smoking article comprises a fuel element comprising acarbonaceous material and at least one catalyst composition, thecatalyst composition comprising ultrafine particles. With reference to acigarette as a smoking article, the cigarette further includes anaerosol generating means, which includes a substrate and at least oneaerosol-forming material. An aerosol-generating means includes anaerosol forming material (e.g. glycerin), tobacco in some form (e.g.tobacco powders, tobacco extract or tobacco dust) and other aerosolforming materials and/or tobacco flavoring agents such as cocoa,licorice, and sugar. The aerosol forming material generally is carriedon a substrate material such as a reconstituted tobacco cut filler or ona substrate such as tobacco cut filler, gathered paper, gathered tobaccopaper, or the like.

In an embodiment of the present invention, the substrate isreconstituted tobacco, which is formed into a continuous rod orsubstrate tube assembly on a conventional cigarette making machine.Typically, the overwrap material for the rod is a barrier material suchas a paper foil laminate. The foil serves as a barrier, and is locatedon the inside of the overwrap. Alternatively, the substrate may be agathered paper formed into a rod or plug. When the substrate is apaper-type material, it can be positioned in a spaced-apart relationshipfrom the fuel element comprising a carbonaceous material and a catalystcomposition. A spaced-apart relationship is desired to minimize contactbetween the fuel element and the substrate, thereby preventing migrationof the aerosol forming materials to the fuel element, as well aslimiting the scorching or burning of the paper substrate. The spacing isnormally provided during manufacture of the cigarette in accordance withone method of making the present invention. Appropriately spacedsubstrate plugs are overwrapped with a barrier material to form asubstrate tube assembly having spaced substrate plugs therein. Thesubstrate tube assembly is cut between the substrate plugs to formsubstrate sections. The substrate sections include a tube with asubstrate plug and void(s), which can be at each end.

The barrier material for making the tube aids in preventing migration ofthe aerosol former to other components of the cigarette. The barriermaterial forming the tube is a relatively stiff material so that whenformed into a tube, it will maintain its shape and will not collapseduring manufacture and use of the cigarette.

In embodiments of the present invention, fuel elements of a smokingarticle can be advantageously circumscribed by an insulating and/orretaining jacket material. The insulating and retaining material isadapted such that drawn air can pass therethrough, and is positioned andconfigured so as to hold the fuel element in place. The jacket is flushwith the ends of the fuel element, however, it may extend from about 0.5mm to about 3 mm beyond each end of the fuel element.

The components of the insulating and/or retaining material whichsurrounds the fuel element can vary. Examples of suitable materialsinclude glass fibers and other materials as described in U.S. Pat. No.5,105,838; European Patent Publication No. 339,690; and pages 48-52 ofthe RJR Monograph, supra. Examples of other suitable insulating and/orretaining materials are glass fiber and tobacco mixtures such as thosedescribed in U.S. Pat. Nos. 5,105,838, 5,065,776 and 4,756,318; and U.S.patent application Ser. No. 07/354,605, filed 22 May 1989 now U.S. Pat.No. 5,119,837.

Other suitable insulating and/or retaining materials are gatheredpaper-type materials which are spirally wrapped or otherwise woundaround the fuel element, such as those described in U.S. patentapplication Ser. No. 07/567,520, filed 15 Aug. 1990, now U.S. Pat. No.5,105,836. The paper-type materials can be gathered or crimped andgathered around the fuel element; gathered into a rod using a rod makingunit available as CU-10 or CU2OS from DeCoufle s.a.r.b., together with aKDF-2 rod making apparatus from Hauni-Werke Korber & Co., KG, or theapparatus described in U.S. Pat. No. 4,807,809 to Pryor et al.; woundaround the fuel element about its longitudinal axis; or provided aslongitudinally extending strands of paper-type sheet using the types ofapparatus described in U.S. Pat. No. 4,889,143 to Pryor et al. and U.S.Pat. No. 5,025,814 to Raker, the disclosures of which are incorporatedherein by reference.

If desired, the fuel element may be extruded into the insulating jacketmaterial as set forth in U.S. patent application Ser. No. 07/856,239,filed 25 Mar. 1992, the disclosure of which is incorporated herein byreference.

Examples of paper-type sheet materials are available as P-2540-136-Ecarbon paper and P-2674-157 tobacco paper from Kimberly-Clark Corp.; andthe longitudinally extending strands of such materials (e.g., strands ofabout 1/32 inch width) extend along the longitude of the fuel element.The fuel element also can be circumscribed by tobacco cut filler (e.g.,flue-cured tobacco cut filler treated with about 2 weight percentpotassium carbonate). The number and positioning of the strands or thepattern of the gathered paper is sufficiently tight to maintain, retainor otherwise hold the composite fuel element structure within thecigarette.

In embodiments of the present invention, the fuel element-jacketassembly is combined with a substrate section or substrate tube assemblyby a wrapper material, which has a propensity not to burn, to form afuel element/substrate section. In some embodiments of the cigarettes,the wrapper typically extends from the mouthend of the substratesection, over a portion of the jacketed fuel element, whereby it isspaced from the lighting end of the fuel element. The wrapper materialassists in limiting the amount of oxygen which will reach the burningportion of the fuel element during use, thereby causing the fuel elementto extinguish after an appropriate number of puffs. In an embodiment ofthe cigarette, the wrapper is a paper/foil/paper laminate. The foilprovides a path to assist in dissipating or transferring the heatgenerated by the fuel element during use. The jacketed fuel element andthe substrate section are joined by the overwrap.

A tobacco section can be formed by a reconstituted tobacco cut fillerrod, made on a typical cigarette making machine, and cut intoappropriate lengths. A filter rod is formed and cut into appropriatelengths for joining to the tobacco section to form a mouthend section.The fuel element/substrate section and the mouthend section are joinedby aligning the reconstituted ends of each section, and overwrapped toform a cigarette.

When a paper substrate is used, a tobacco paper rod and a reconstitutedcut filler rod are formed and cut into appropriate lengths and joined toform a tobacco section. The tobacco section and the fuel elementassembly/substrate section are joined by aligning the tobacco paper plugend of the tobacco section with the substrate end of the fuel elementassembly/substrate section and joining the sections with a wrapper whichextends from the rear end of the tobacco roll to an appropriate lengthpast the junction of the two sections for forming the tobacco roll/fuelelement assembly. The tobacco roll/fuel element assembly is then joinedto a filter by a tipping material.

As described above, the substrate carries aerosol forming materials andother ingredients, e.g., flavorants and the like, which, upon exposureto heated gases passing through the aerosol generating means duringpuffing, are vaporized and delivered to the user as a smoke-likeaerosol. Aerosol forming materials used herein include glycerin,propylene glycol, water, and the like, flavorants, and other optionalingredients. The patents referred to in the Background of the Invention(supra) teach additional useful aerosol forming materials that need notbe repeated here.

Cast sheets of tobacco dust or powder, a binder, such as an alginatebinder, and glycerin can also be used to form useful substrates herein.Suitable cast sheet materials for use as substrates are described inU.S. Pat. No. 5,101,839 and U.S. patent application Ser. No. 07/800,679,filed Nov. 27, 1991.

Suitable cast sheet materials typically contain between about 30 to 75weight percent of an aerosol former such as glycerin; about 2 to 15weight percent of a binder, such as ammonium alginate; 0 to about 2weight percent of a sequestering agent such as potassium carbonate;about 15 to about 70 to 75 weight percent of organic, inorganic fillermaterials, or mixtures thereof, such as tobacco dust, aqueous extractedtobacco powder, starch powder, rice flower, ground puffed tobaccos,carbon powder, calcium carbonate powder, and the like, and from about 0to about 20 weight percent of flavors such as tobacco extracts, and thelike.

In one embodiment, a cast sheet material includes 60 weight percentglycerin, 5 weight percent ammonium alginate binder, 1 weight percentpotassium carbonate, 2 weight percent flavors such as tobacco extractsand 32 weight percent aqueous extracted tobacco powder.

The cast sheets are formed by mixing aqueous extracted tobacco powder,water and the potassium carbonate in a high sheer mixer to produce asmooth, flowable paste. Glycerin and ammonium alginate are then addedand the high shear mixing is continued until a homogenized mixture isproduced. The homogenized mixture is cast on a heated belt (about200.degree. F.) with a 0.0025 to 0.0035 inch casting clearance and isdried to yield a 0.0004 to 0.0008 inch thick sheet under hightemperature air (about 200.degree. to 250.degree. F.). The sheet isdoctored from the belt and either wound onto spools for slitting intowebs or chopped into rectangular pieces about 2 inches by 1 inch whichare formed into cut filler. If the cast sheet material is used in a webor cut filler form, normally the substrate will be from about 10 mm to40 mm in length and extend from the rear end of the fuel element to thetobacco segment or the front end of an extra long filter segment (e.g.,about 30 mm to 50 mm in length). In such instances the tobacco paperplug can be omitted.

In embodiments of the present invention, the combination of the fuelelement and the substrate (also known as the front end assembly) isattached to a mouthend piece; although a disposable fuelelement/substrate combination can be employed with a separate mouthendpiece, such as a reusable cigarette holder. The mouthend piece providesa passageway which channels vaporized aerosol forming materials into themouth of the smoker; and can also provide further flavor to thevaporized aerosol forming materials.

Flavor segments (i.e., segments of gathered tobacco paper, tobacco cutfiller, or the like) can be incorporated in the mouthend piece or thesubstrate segment, e.g., either directly behind the substrate or spacedapart therefrom, to contribute flavors to the aerosol. Gathered carbonpaper can be incorporated, particularly in order to introduce mentholflavor to the aerosol. Such papers are described in European PatentPublication No. 342,538. Other flavor segments useful herein aredescribed in U.S. patent application Ser. No. 07/414,835, filed 29 Sep.1989, now U.S. Pat. No. 5,076,295 Ser. No. 07/606,287, filed 6 Nov.1990; now U.S. Pat. No. 5,105,834 and Ser. No. 07/621,499, filed 7 Dec.1990, now abandoned.

FIG. 1 illustrates a smoking article according to an embodiment of thepresent invention. The smoking article depicted in FIG. 1 comprises afuel element 10 of the present invention comprising a carbon source andat least one catalytic composition comprising ultrafine particles of ametal oxide and/or metal. The fuel element displays a plurality ofpassageways 11 therethrough, about thirteen passageways altogether. Thefuel element 10 is surrounded by insulating sheet material 16 having aplurality of grooves which facilitate the formation of the sheetmaterial into a jacket surrounding the fuel element. In embodiments ofthe smoking article, the jacket can be made of calcium sulfate (CaSO₄).

A metallic capsule 12 overlaps a portion of the mouthend of the fuelelement 10 and encloses the physically separate aerosol generating meanswhich contains a substrate material 14. The substrate material carriesone or more aerosol forming materials. The substrate may be inparticulate form, in the form of a rod, and other geometric shapesadvantageous for generating an aerosol.

Capsule 12 is circumscribed by a roll of tobacco 18. Alternatively, inother smoking articles, the capsule may be circumscribed with anadditional or continuous jacket of an insulating sheet material.Insulating sheet materials suitable for use in smoking articles of thepresent invention are further described in U.S. Pat. No. 5,303,720 toBanerjee which is hereby incorporated by reference. Two slit-likepassageways 20 are provided at the mouth of the capsule in the center ofthe crimped tube.

At the mouth end of the tobacco roll 18, is a mouthend piece 22,comprising a cylindrical segment of a flavored carbon filled sheetmaterial 24 and a segment of non-woven thermoplastic fibers 26 throughwhich the aerosol passes to the user. The smoking article, or portionsthereof, is overwrapped with one or more layers of cigarette papers30-36

In some embodiments, catalyst compositions comprising metal oxide and/ormetal ultrafine particles are incorporated into the filter element ofthe smoking article as described in U.S. patent application Ser. No.10/730,962 which is hereby incorporated by reference.

In certain embodiments of the cigarettes of the present invention,convective heating is the predominant mode of energy transfer from theburning fuel element comprising a carbonaceous material and at least onecatalyst composition to the aerosol-generating means disposedlongitudinally behind the fuel element. When a foil/paper laminate isused as an overwrap to join the fuel/substrate section some heat may betransferred to the substrate by the foil layer. As described above, theheat transferred to the substrate volatilizes the aerosol-formingmaterial(s) and any flavorant materials carried by the substrate, and,upon cooling, these volatilized materials are condensed to form asmoke-like aerosol which is drawn through the cigarette during puffing,and which exits the filter piece. This smoke-like aerosol can containreduced amounts of carbon monoxide resulting from the reduced carbonmonoxide production of a fuel element of the present invention uponcombustion.

In some embodiments, the catalyst compositions can be deposited on aporous support such as graphite or alumina wherein the porous support isplaced behind the fuel in an end to end relationship.

In a further aspect, the present invention provides a method forfacilitating the reduction in the amount of carbon monoxide produced bya smoking article, comprising incorporating at least one catalystcomposition comprising ultrafine particles of a metal oxide and/or metalinto the fuel element of a smoking article.

In another aspect, the present invention provides methods and apparatusfor the simultaneous quantification of the carbon monoxide content andcarbon dioxide content of a gaseous mixture. In an embodiment, a methodfor quantifying the carbon monoxide content and carbon dioxide contentof a gaseous mixture comprises injecting the gaseous mixture into asplit injection tube of a gas chromatograph through a single injector,resolving a relative carbon monoxide content of the gaseous mixture on afirst chromatographic column, simultaneously resolving a relative carbondioxide content on a second chromatographic column, and detecting andquantifying the eluate carbon monoxide and carbon dioxide with a massspectrometer. In further embodiments, the gaseous mixture containingcarbon monoxide and carbon dioxide comprises mainstream smoke or asmoke-like aerosol produced from a smoking article.

Under some circumstances, carbon monoxide and carbon dioxide can beresolved on a single chromatographic column. Single columns that arecapable of resolving both carbon monoxide and carbon dioxide, however,use carrier gas at flow rates that are too high for use with a massspectrometer. As a result, their use precludes the numerous advantagesgained by the two-dimensional analysis of GC/MS. Moreover, other singlechromatographic columns that use a carrier gas at acceptable flow ratesfor use with a mass spectrometer cannot effectively resolve both carbonmonoxide and carbon dioxide.

The utilization of dual chromatographic columns allows for the completeresolution of the carbon monoxide and carbon dioxide contents of thegaseous mixture at flow rates that are acceptable for use with a massspectrometer. The two-dimensional analysis provided by gaschromatography/mass spectrometry (GC/MS) can provide precise relativequantifications of carbon monoxide and carbon dioxide amounts present ingaseous mixtures.

FIG. 2 illustrates a flowchart for the quantification of carbon monoxideand carbon dioxide contents of a gaseous mixture according to anembodiment of the present invention. In particular embodiments, thegaseous mixture comprises mainstream smoke or smoke-like aerosol from asmoking article. The gaseous mixture is injected into the split injectorof the gas chromatogram 201. The split injector 201 splits the gaseousmixture for simultaneous resolution on dual chromatographic columns. Thecarbon monoxide content of the mainstream smoke is resolved on a firstchromatographic column 202, and the carbon dioxide content issimultaneously resolved on a second chromatographic column 203. Thefirst chromatographic column can be selected for optimal resolution ofcarbon monoxide while the second chromatographic column can be selectedfor the optimal resolution of carbon dioxide. For example, a Molsievecolumn can be used to resolve carbon monoxide and a wide-boreGS-CarbonPLOT column can be used to resolve carbon dioxide.

Once resolved, the carbon monoxide content and carbon dioxide content ofthe mainstream smoke are quantified by a mass spectrometer 204. The useof a mass spectrometer adds a second dimension of analysis that is notpresent with traditional gas chromatographic detection devices. A massspectrometer can further resolve the carbon monoxide content and carbondioxide content of a gaseous mixture allowing for greater accuracy andprecision when quantifying these chemical species.

In an embodiment, an apparatus for quantifying the carbon monoxidecontent and carbon dioxide content of a gaseous mixture comprises: a gaschromatograph comprising a single split injector, dual chromatographiccolumns; and a mass spectrometer.

FIG. 3 illustrates an apparatus for the simultaneous quantification ofthe carbon monoxide content and carbon dioxide content of a gaseousmixture comprising the two-dimensional analysis of gas chromatographyand mass spectrometry in an embodiment according to the presentinvention. The gas chromatograph 301 comprises a single injector 302which splits the sample onto two chromatographic columns 303, 304. Thetemperature of the split single injector 302 can be varied in accordancewith desired analytical conditions. The temperature variance of thesingle split injector 302 can be controlled manually by a user or can becontrolled electronically with any processor-equipped device such as acomputer and/or dedicated controller. As previously discussed, one ofthe two columns 303 is suitable for resolving the carbon monoxidecontent of a gaseous mixture while the other column 304 is suitable forresolving the gaseous mixture's carbon dioxide content. Chromatographiccolumns for use in the gas chromatograph of the present apparatus areavailable commercially.

The two chromatographic columns feed into a mass spectrometer 305. Massspectrometers suitable for use in further resolving and quantifying thecarbon monoxide content and carbon dioxide content eluting from the twocolumns of the gas chromatograph can comprise mass analyzers comprisingmagnetic sector analyzers, double-focusing spectrometers, quadrupolemass filters, ion trap analyzers, and time-of-flight (TOF) analyzers.

The embodiments described above in addition to other embodiments can befurther understood with reference to the following examples. Several ofthe fuel elements provided in the examples below comprise percentages ofBKO carbon, Guar gum, graphite, and tobacco. Combustion of all the fuelelements in the examples below provides energy used to generate aerosolfrom tobacco and other aerosol formers like glycerin. Combustion of thefuel elements, however, also produces carbon monoxide and carbondioxide. Moreover, complete combustion of the fuel elements produces amaximum amount of energy and a carbon dioxide by-product. Completecombustion is demonstrated by the chemical reaction:C (s)+O₂ (g)→CO₂ (g)Incomplete combustion, nevertheless, produces much less energy and asubstantial carbon monoxide by-product. Incomplete combustion isdemonstrated by the reaction sequence:C (s)+O (g)→CO (g)C (s)+O₂ (g)→CO₂ (g)As a result, complete combustion of the fuel element in desirable.

Graphite in the fuel elements comprising graphite, BKO carbon, Guar gum,and tobacco, is inactive up to the temperatures attained by combustionof the fuel element and remains substantially unchanged throughout thecombustion of the fuel element. The remaining three carbonaceouscomponents undergo oxidation during the combustion to provide energy andoxides of carbon. Among the carbonaceous components, BKO carbon is themajor component and hence chosen for the study of the fuel elements inthe examples below.

EXAMPLE 1

Several materials were prepared to evaluate the efficacy of a method andapparatus for simultaneously resolving the carbon monoxide content andcarbon dioxide content of a gaseous mixture according to an embodimentof the present invention. The materials prepared for analysis by themethod and apparatus were a standard gaseous mixture (CO:CO₂:N₂),tobaccos from 1R4F cigarettes, and 1R4F cigarette smoke. A smallquantity of each sample was heated to 700° C. for 20 seconds in thepresence of air. The standard gaseous mixture was analyzed in theabsence of air to preserve the composition of the sample. A pyroprobewas used for sample heating. The temperatures of the pyroprobe interfaceand the gas chromatograph injector were set at ambient temperature. Thegas chromatograph utilized was a Hewlett-Packard 5890 Series II. Asingle injection onto dual chromatographic columns was used for thecarbon monoxide and carbon dioxide analysis. A Molsieve column(Chrompack, 25 M×0.32 mm I.D., 30 μm film) was used for carbon monoxideresolution, and a GS-CarbonPLOT column (J&W Scientific, 60 M×0.32 mmI.D., 1.5 μm film) was used for carbon dioxide resolution. Thetemperatures of the columns were held at 35° C. for 10 minutes,programmed to 150° C. at 25° C./min and held for 10 min. A single massspectrometer was used to identify and quantify the resolved carbonmonoxide and carbon dioxide peaks eluting from the chromatographiccolumns. The mass spectrometer utilized was a Hewlett-Packard 5972 massselective detector. The mass spectrometer was operated at 70 eV in theEI mode with the temperature of the ion source being maintained at 180°C. The mass range scanned was 20-200 atomic mass units. The carbonmonoxide and carbon dioxide quantified were only a fraction of the totalcarbon monoxide and carbon dioxide generated from the heated materials.Only the resolved carbon monoxide and carbon dioxide peak areas wereused for quantification.

The results of the standard gaseous mixture resolved on the dualchromatographic columns are illustrated in FIG. 4. The ion chromatogramof FIG. 4 demonstrates a completely resolved carbon monoxide peak and acompletely resolved carbon dioxide peak. For comparative purposes, thestandard gaseous mixture (CO:CO₂:N₂) was injected and resolved on singlecolumn gas chromatographs under experimental conditions consistent withresolution on dual chromatographic columns. The standard gaseous mixturewas resolved on a single column gas chromatograph comprising a Molsievecolumn. The results are illustrated in FIG. 5. As demonstrated in theion chromatogram of FIG. 5, the Molsieve column completely resolved thecarbon monoxide content but failed to completely resolve the carbondioxide content of the standard gaseous mixture. Similarly, the standardgaseous mixture was additionally resolved on a single GS-CarbonPLOTchromatographic column. The results of this resolution are illustratedin FIG. 6. The ion chromatogram of FIG. 6 displays a complete resolutionof carbon dioxide and an incomplete resolution of carbon monoxide. Thecarbon monoxide co-eluted with nitrogen and oxygen.

The results of the remaining sample materials comprising tobaccos from1R4F cigarettes and 1R4F cigarette smoke resolved on dualchromatographic columns in accordance with the present invention areillustrated in FIGS. 7 and 8 respectively. The ion chromatograms ofFIGS. 7 and 8 demonstrate completely and sharply resolved carbonmonoxide and carbon dioxide peaks.

EXAMPLE 2

Seven samples were generated for analysis of carbon monoxide/carbondioxide (CO/CO₂) ratios. These samples were: (1) Control Carbon Black950, (2) Carbon Black 950 with 5% Fe₂O₃ ultrafine particles, (3) CarbonBlack 950 with 2% Fe₂O₃ ultrafine particles, (4) Carbon Black 950 with5% TiO₂—Au ultrafine particles and (5) Carbon Black 950 with 2% TiO₂—Auultrafine particles, (6) Carbon Black 950 with 5% CeO₂ ultrafineparticles, and (7) Carbon Black 950 with 2% CeO₂ ultrafine particles.

To simulate combustion of the fuel element, a pyroprobe was used to heata small quantity of each sample to 700° C. for 20 seconds in thepresence of air. 700° C. is the average temperature of a fuel elementduring combustion. The gaseous mixture resulting from the combustion ofeach sample was analyzed in accordance with the method delineated inFIG. 2. The pyroprobe and gas chromatogram injector were set at ambienttemperature. A Molsieve chromatographic column was used for carbonmonoxide resolution and a GS-CarbonPLOT chromatographic column was usedfor carbon dioxide resolution. A mass spectrometer was used as a seconddimension of analysis in the quantification of the carbon monoxide andcarbon dioxide contents generated by the samples. It should be notedthat the carbon monoxide and the carbon dioxide contents quantified wereonly a fraction of the carbon monoxide and carbon dioxide contentsproduced by the samples and that the resolved peak areas were used forquantification. Table 1 summarizes the results produced by the samplesin this example. TABLE 1 MASS ABUNDANCE (COUNTS)^(A) CO/CO₂ SAMPLES COCO₂ Ratio (1) Control Carbon 383,013,104 1,284,639,516 0.298 (2) Carbonand 5% Fe₂O₃ 53,357,015 1,202,285,067 0.0444 (3) Carbon and 2% Fe₂O₃65,069,392 1,093,984,395 0.0595 (4) Carbon and 5% TiO₂-Au 131,461,228926,581,662 0.142 (5) Carbon and 2% TiO₂-Au 264,095,113 956,314,4080.276 (6) Carbon and 5% CeO₂ 268,205,948 965,498,063 0.278 (7) Carbonand 2% CeO₂ 279,547,847 977,688,888 0.286 Air Blank 655,583 7,602,213^(A)Mass abundance is the total abundance of ions in a mass spectrum forcompound with unit of counts.

The results displayed in Table 1, which are additionally illustrated inFIG. 9, demonstrate that ferric oxide (Fe₂O₃) ultrafine particleseffectuate a significant reduction in the amount of carbon monoxideproduced by the fuel element. Fuel element sample (2) comprising 5%ferric oxide (Fe₂O₃) ultrafine particles by weight exhibited an 85%reduction in the amount of carbon monoxide produced when heated.Similarly, fuel element sample (3) comprising 2% ferric oxide (Fe₂O₃)ultrafine particles by weight displayed an 80% reduction in the amountof carbon monoxide produced upon sample heating. The titanium oxide-gold(TiO₂—Au) ultrafine particles of sample (4) demonstrated a carbonmonoxide reduction of 52% while the ceric oxide (CeO₂) ultrafineparticles of sample (6) resulted in approximately a 7% reduction.

EXAMPLE 3

Eight fuel element samples were generated for analysis of (CO/CO₂)ratios. These samples were: (1) BKO Carbon 950, (2) BKO Carbon 950 with5% gamma-Fe₂O₃-large particle, (3) BKO 950 Carbon with 5%Fe₂O₃-nanoparticle, (4) BKO 950 Carbon with 2% Fe₂O₃-nanoparticle, (5)Carbon Mix 1 (78.3% BKO 950 Carbon, 10.1% Guar gum, 6.55% graphite, and5.05% tobacco), (6) Carbon Mix 1 with 5% Fe₂O₃-nanoparticle, (7) CarbonMix 2 (82.4% BKO Carbon 950, 10.6% Guar gum, and 7.0% graphite) and (8)Carbon Mix 2 with 5% Fe₂O₃-nanopaticle.

To simulate combustion of the fuel element, a pyroprobe was used to heata small quantity of each sample to 700° C. in the presence of air for 20seconds. 700° C. is the average temperature of a fuel element duringcombustion. The gaseous mixture resulting from the combustion of eachsample was analyzed in accordance with the method delineated in FIG. 2.The pyroprobe and gas chromatogram injector were set at ambienttemperature. A Molsieve chromatographic column was used for carbonmonoxide resolution and a GS-CarbonPLOT chromatographic column was usedfor carbon dioxide resolution. A mass spectrometer was used as a seconddimension of analysis in the quantification of the carbon monoxide andcarbon dioxide contents generated by the samples. It should be notedthat the carbon monoxide and the carbon dioxide contents quantified wereonly a fraction of the carbon monoxide and carbon dioxide contentsproduced by the samples and that the resolved peak areas were used forquantification. Table 2 summarizes the results produced by the samplesin this example. TABLE 2 MASS ABUNDANCE (COUNTS)^(A) SAMPLES CO CO₂CO/CO₂ Ratio (1) BKO Carbon 950 136,632,880 439,836,557 0.311 (2) BKOCarbon 950 and 34,403,969 511,214,899 0.0673 5% γ-Fe₂O₃-large particle(3) BKO 950 and 5% 16,068,614 489,909,229 0.0328 Fe₂O₃-nanoparticle (4)BKO 950 and 2% 26,802,880 508,261,449 0.0527 Fe₂O₃-nanoparticle (5)Carbon Mix 1 98,093,373 458,829,259 0.214 (6) Carbon Mix 1 and 5%89,003,804 491,290,439 0.181 Fe₂O₃-nanoparticle (7) Carbon Mix 2105,287,470 463,439,227 0.227 (8) Carbon Mix 2 and 5% 34,534,408478,608,718 0.0722 Fe₂O₃-nanoparticle^(A)Mass abundance is the total abundance of ions in a mass spectrum forcompound with unit of counts.

The results summarized in Table 2, which are further illustrated in FIG.10, demonstrate that ferric oxide (Fe₂O₃) ultrafine particles caneffectuate a reduction in the amount of carbon monoxide produced by afuel element. Comparison of the CO/CO₂ ratios of sample (2) comprising5% gamma-Fe₂O₃-large particle and sample (3) comprising 5% Fe₂O₃nanoparticle reveals the dependency of catalytic activity on particlesize. The smaller Fe₂O₃ ultrafine particles exhibit a greater surfacearea than the γ—Fe₂O₃-large particles which leads to higher catalystturnover rates and a greater reduction in the amount of carbon monoxideproduced by the fuel element upon heating. The Fe₂O₃ ultrafine particlesof sample (3) reduced the carbon monoxide content of the gaseous mixtureanalyzed by 89.5%, which is an 11% increase over the γ—Fe₂O₃-largeparticles.

The results of the sample testing further demonstrate the catalyticactivity of ferric oxide ultrafine particles in fuel elements thatcomprise the additional components of Guar gum and graphite. Sample (7)is an example of a fuel element containing these additional components.Sample (8) comprises the components of sample (7) with the addition of5% by weight of ferric oxide (Fe₂O₃) ultrafine particles. The ferricoxide (Fe₂O₃) ultrafine particles reduced the carbon monoxide productionof the fuel element of sample (8) by 68% in comparison with sample (7)which did not contain ferric oxide (Fe₂O₃) ultrafine particles.

Fuel elements containing tobacco components were additionally analyzedin this example. Sample (5) is a fuel element containing a 5.05% tobaccocontent in addition to BKO Carbon 950, Guar gum, and graphite. Sample(6) comprises the components of sample (5) with the addition of 5% byweight of ferric oxide (Fe₂O₃) nanoparticle. The ferric oxide (Fe₂O₃)ultrafine particles reduced the carbon monoxide production of the fuelelement of sample (6) by 15.4% in comparison with sample (5) which didnot contain ferric oxide (Fe₂O₃) ultrafine particles. The catalyticactivity of the ferric oxide (Fe₂O₃) ultrafine particles in sample (6)was diminished due to the tobacco content in the fuel elementcomposition. The combustion of tobacco produces several chemical speciesthat inhibit the catalytic behavior of the ultrafine particles. Thiscatalytic inhibition is displayed in the 15.4% reduction of carbonmonoxide production.

EXAMPLE 4

Seven carbon samples were generated for analysis of CO/CO₂ ratios. Thesample were: (1) Control Carbon (BKO 950), (2) Carbon with 5% Fe₂O₃ultrafine particles obtained from MACH-1, Inc., (3) Carbon with 5% Al₂O₃ultrafine particles obtained from NEI, Inc., (4) Carbon with 5% CeO₂ultrafine particles obtained from NEI, Inc., (5) Carbon with 5% TiO₂ultrafine particles obtained from NEI, Inc., (6) Carbon with 5% tobaccoand 5% Fe₂O₃ ultrafine particles obtained from MACH-1, Inc., and (7)Carbon with 5% tobacco (heat treated) and 5% Fe₂O₃ ultrafine particlesobtained from MACH-1, Inc.

To simulate combustion of the fuel element, a pyroprobe was used to heata small quantity of each sample to 700° C. in the presence of air for 20seconds. 700° C. is the average temperature of a fuel element duringcombustion. The gaseous mixture resulting from the combustion of eachsample was analyzed in accordance with the method delineated in FIG. 2.The pyroprobe and gas chromatogram injector were set at ambienttemperature. A Molsieve chromatographic column was used for carbonmonoxide resolution and a GC-CarbonPLOT chromatographic column was usedfor carbon dioxide resolution. A mass spectrometer was used as a seconddimension of analysis in the quantification of the carbon monoxide andcarbon dioxide contents generated by the samples. It should be notedthat the carbon monoxide and the carbon dioxide contents quantified wereonly a fraction of the carbon monoxide and carbon dioxide contentsproduced by the samples and that the resolved peak areas were used forquantification. Table 3 summarizes the results produced by the samplesin this example. TABLE 3 CO/ MASS ABUNDANCE CO₂ (COUNTS)^(B) Ra-SAMPLES^(A) CO CO₂ tio (1) Control Carbon (BKO 349,722,771 1,097,283,1050.319 950) (2) Carbon and 5% Fe₂O₃ 73,461,112 1,171,782,023 0.0627ultrafine particles (3) Carbon and 5% Al₂O₃ 323,332,586 988,477,6730.327 ultrafine particles (4) Carbon and 5% CeO₂ 285,376,4771,032,058,820 0.277 ultrafine particles (5) Carbon and 5% TiO₂379,654,967 1,164,775,102 0.326 ultrafine particles (6) Carbon, 5%Tobacco, 184,501,337 1,042,248.352 0.177 and 5% Fe₂O₃ ultrafineparticles (7) Carbon, 5% Tobacco^(c), 199,972,837 1,165,685,787 0.172and 5% Fe₂O₃ ultrafine particles Air Blank 2,501,751 12,070,258^(A)All carbon samples were baked at 950 C. prior to the analysis.^(B)Mass abundance is the total abundance of ions in a mass spectrum forcompound with unit of counts.^(c)Tobacco was heat-treated at 100° C. for 4 hours.

The results summarized in Table 3 and further illustrated in FIG. 11reiterate the efficacy of ferric oxide (Fe₂O₃) ultrafine particles inreducing the carbon monoxide production of fuel elements according tothe present invention. When compared to titanium oxide (TiO₂), aluminumoxide (Al₂O₃), and ceric oxide (CeO₂) ultrafine particles, ferric oxide(Fe₂O₃) ultrafine particles demonstrate a greater reduction in thecarbon monoxide production of heated fuel elements. In this example,samples (3) and (5) containing aluminum oxide (Al₂O₃) and titanium oxide(TiO₂) ultrafine particles respectively exhibited a slight increase incarbon monoxide content. Moreover, sample (4) comprising ceric oxide(CeO₂) ultrafine particles displayed a carbon monoxide reduction of 13%.Sample (2) comprising ferric oxide (Fe₂O₃) ultrafine particles, however,exhibited a carbon monoxide reduction of 80%.

In samples (6) and (7), ferric oxide (Fe₂O₃) ultrafine particles wereadditionally incorporated into fuel elements that contained tobacco aswell. The reduction of carbon monoxide produced from these fuel elementswhen heated was diminished due to the catalyst poisoning chemicalspecies generated upon tobacco combustion.

EXAMPLE 5

Seven tobacco samples were generates for analysis of CO/CO₂ ratios. Thesamples were: (1) Control Camel LT® Tobacco, (2) Camel LT® Tobacco with5% Fe₂O₃ ultrafine particles, (3) Camel LT® Tobacco with 2% Fe₂O₃ultrafine particles (4) Camel LT® Tobacco with 5% TiO₂—Au ultrafineparticles, (5) Camel LT® Tobacco with 2% TiO₂—Au ultrafine particles,(6) Camel LT® Tobacco with 5% CeO₂ ultrafine particles, and (7) CamelLT® Tobacco with 2% CeO₂ ultrafine particles.

A Chemical Data System (CDS) Model 2000 pyroprobe was used for sampleheating. A small quantity of each sample (approximately 7 mg) was heatedat 700° C. in the presence of air for 20 seconds. The gaseous mixtureresulting from the heating of each sample was analyzed in accordancewith the method delineated in FIG. 2. The temperatures of the pyroprobeinterface and the injector on the gas chromatogram were set at ambienttemperature. The GC used was a Hewlett-Packard 5890 Series II gaschromatograph. A single injection onto dual columns was used for CO andCO₂ analysis. A Molsieve column (Chrompack, 25 M×0.32 mm I.D., 30 μmfilm) was used for CO analysis. A GS-CarbonPLOT column (J&W Scientific,60 M×0.32 mm I.D., 1.5 μm film) was used for CO₂ analysis. Thetemperature of the CG columns was held at 35° C. for 10 minutes,programmed to 150° C. at 25° C./min and held for 10 min. A massspectrometer (MS) was used to identify and quantify the resolved CO andCO₂ peaks eluting from the gas chromatograph. The MS used was aHewlett-Packard 5972 mass selective detector. The mass spectrometer wasoperated at 70 eV in the El mode. The temperature of the ion source wasmaintained at 180° C. and the mass range scanned was 20-200 atomic massunits. It should be noted that the CO and CO₂ quantities determined wereonly a fraction of the total CO and CO₂ content generates from thesamples. Only the resolved CO and CO₂ peak areas were used forquantification. Table 4 summarizes the results produced by the samplesin this example. TABLE 4 MASS ABUNDANCE (COUNTS)^(A) CO/CO₂ SAMPLES COCO₂ Ratio (1) Camel LT Tobacco 544,728,554 1,383,849,048 0.394 (2) CamelLT ® Tobacco 526,196,075 1,343,828,130 0.392 with 5% Fe₂O₃ (3) CamelLT ® Tobacco 532,589,297 1,354,841,196 0.393 with 2% Fe₂O₃ (4) CamelLT ® Tobacco 540,678,974 1,370,604,676 0.395 with 5% TiO₂-Au (5) CamelLT ® Tobacco 536,124,377 1,392,004,504 0.385 with 2% TiO₂-Au (6) CamelLT ® Tobacco 529,191,513 1,361,128,568 0.389 with 5% CeO₂ (7) Camel LT ®Tobacco 523,482,876 1,365,668,545 0.383 with 2% CeO₂ Air Blank 655,5837,602,213^(A)Mass abundance is the total abundance of ions in a mass spectrum foreach compound with unit of counts.

The results summarized in Table 4 and further illustrated in FIG. 12display that the catalytic activities of the metal and metal-oxideultrafine particles comprising the catalyst compositions of the presentinvention are inhibited when combined with only tobacco to compose afuel element. These results are consistent with fuel element samples ofprevious examples that contained specific amounts of tobacco. Whenheated or combusted, the tobacco content of the fuel element producesseveral chemical species that poison the catalytic ultrafine particlesand thereby significantly reduce, if not eliminate, the catalyticoxidation of carbon monoxide to carbon dioxide. Consequently, tobaccocomponents of fuel elements according to the present invention aredisfavored. As displayed in the previous examples, however, a smallcomponent of tobacco within the fuel element does not destroy thecatalytic activity of the metal oxide and metal ultrafine particles anappreciable amount and is, therefore, tolerable. The inclusion of atobacco component in the fuel element of a smoking article can providemore flavor to the aerosol comprising the mainstream smoke of a smokingarticle.

1. A fuel element comprising: a carbonaceous material; and at least onecatalyst composition comprising ultrafine particles of a metal oxide,metal, or mixtures thereof.
 2. The fuel element of claim 1, wherein themetal oxide comprises ferric oxide.
 3. The fuel element of claim 1,wherein the metal comprises gold, copper, silver, platinum, palladium,rhodium, nickel, and mixtures thereof.
 4. The fuel element of claim 1,wherein the catalyst composition comprises up to 5% by weight of thefuel element.
 5. The fuel element of claim 1 wherein the ultrafineparticles have an individual particle size up to about 1 micrometer. 6.The fuel element of claim 1, wherein the ultrafine particles have anindividual particle size of up to about 5 nanometers.
 7. The fuelelement of claim 1, wherein the ultrafine particles have an individualparticle size between about 2 and about 4 nanometers.
 8. A smokingarticle comprising: a fuel element comprising a carbonaceous materialand at least one catalyst composition comprising ultrafine particles ofa metal oxide, metal, or mixtures thereof; and a physically separateaerosol generating means comprising at least one aerosol formingmaterial.
 9. The smoking article of claim 8 wherein the metal oxidecomprises ferric oxide.
 10. The smoking article of claim 8, wherein thecatalyst composition is operable to convert carbon monoxide to carbondioxide at temperatures between about 700° C. and about 950° C.
 11. Amethod for reducing carbon monoxide production of a fuel elementcomprising: incorporating a catalyst composition into the fuel element,the catalyst composition comprising: ultrafine particles of a metaloxide, metal, or mixtures thereof.
 12. The method of claim 11, whereinincorporating a catalyst composition into the fuel element compriseswash coating, dipping, painting, or spraying the fuel element with thecatalyst composition.
 13. The method of claim 11, wherein incorporatinga catalyst composition into the fuel element comprises placing thecatalyst composition in an inner core of the fuel element wherein theinner core is surrounded by an outer shell comprising carbonaceousmaterial.
 14. The method of claim 11, wherein incorporating a catalystcomposition into a fuel element comprises placing the catalystcomposition on a substrate located behind the fuel element.
 15. Themethod of claim 14, wherein the substrate comprises an inert carbonmaterial or a porous material.
 16. A method for simultaneouslyquantifying a carbon monoxide content and a carbon dioxide content of agaseous mixture comprising: injecting the gaseous mixture into a splitsingle injector of a gas chromatogram; resolving the carbon monoxidecontent of the gaseous mixture on a first chromatographic column andsimultaneously resolving the carbon dioxide content of the gaseousmixture on a second chromatographic column; and detecting andquantifying the resolved carbon monoxide content and carbon dioxidecontent with a mass spectrometer.
 17. The method of claim 16, whereinthe gaseous mixture comprises smoke from a smoking article, mainstreamsmoke from a smoking article, smoke-like aerosol from a smoking article,or mixtures thereof.
 18. An apparatus for simultaneously quantifying acarbon monoxide content and a carbon dioxide content of a gaseousmixture comprising: a gas chromatograph comprising a split singleinjector and two chromatographic columns; and a mass spectrometer. 19.The apparatus of claim 18, wherein one of the chromatographic columnspossesses the ability to resolve carbon monoxide from a gaseous mixture,and the remaining chromatographic column possesses the ability toresolve carbon dioxide from a gaseous mixture.
 20. The apparatus ofclaim 18, wherein the temperature of the split single injector of thegas chromatograph is variable.